Method For Determining Residues in Plastics

Abstract

The present invention relates to a method for determining dangerous or pesticidal residues in plastics, which comprises processing a plastic sample to a fine powder, converting the powder into a form accessible for determining the analyte, and determining the analyte. The present invention is thus concerned with the analysis of plastics, in particular trace analysis of residues in plastics. The method advantageously allows the use of microextraction techniques and thus a high sample throughput. The method is especially useful for determining whether or not a plastic sample such as agricultural waste plastics contain pesticidal residues.

1 - 29 . (canceled) 
   
   
       30 . Method for determining a dangerous analyte in plastics, which comprises processing a plastic sample to a powder having a particle size of 800 μm or less, treating the powder or a portion thereof with solvent capable of dissolving the analyte thereby providing a solution that contains the analyte, and determining the analyte. 
   
   
       31 . The method of  claim 30 , wherein the dangerous analyte is a T+ compound. 
   
   
       32 . The method of  claim 31 , wherein the T+ compound is selected from the group consisting of 2-ethylhexanoic acid chloride, isononanoic acid chloride, neodecanoic acid chloride, hydrofluoric acid, atropine sulfate, scopolamine hydrobromide, 13-acetyldigoxine, epinephrine bitartrate, pilocarpine hydrochloride, hyoscyamine sulfate, hyoscyamine hydrobromide, atropine methylnitrate, alkylated phenol, dimethylsulfate, p-chloro-o-nitroaniline, and 5-chloro-2-nitroaniline. 
   
   
       33 . Method for determining a pesticidal analyte in plastics, which comprises processing a plastic sample to a powder having a particle size of 800 μm or less, treating the powder with solvent capable of dissolving the analyte thereby providing a solution that contains the analyte, and determining the analyte. 
   
   
       34 . The method of  claim 33 , wherein the pesticidal analyte is a pesticide. 
   
   
       35 . The method of  claim 30 , wherein the sample comprises less than 1% by weight of the dangerous or pesticidal analyte. 
   
   
       36 . The method of  claim 30 , wherein the plastic sample is agricultural waste plastic. 
   
   
       37 . The method of  claim 30 , wherein the plastic sample comprises poly(ethylene), poly(propylene) or poly(ethylene terephthalate). 
   
   
       38 . The method of  claim 30 , wherein the sample has a weight in the range of 500 to 25.000 g. 
   
   
       39 . The method of  claim 30 , wherein the processing of the sample comprises subjecting the sample to size reduction. 
   
   
       40 . The method of  claim 39 , wherein size reduction comprises a first step of shredding the sample to yield a particulate material and a second step of milling the particulate material to yield the fine powder. 
   
   
       41 . The method of  claim 40 , wherein the particulate material has a particle size of 1.0 to 2000 mm. 
   
   
       42 . The method of  claim 40 , wherein milling is ultracentrifugal milling. 
   
   
       43 . The method of  claim 40 , wherein milling is performed at reduced temperature. 
   
   
       44 . The method of  claim 30 , wherein particle size is determined by sieve analysis. 
   
   
       45 . The method of  claim 44 , wherein the powder has a particle size of 700 μm or less, or of 600 μm or less. 
   
   
       46 . The method of  claim 30 , wherein the powder has a volume-weighted particle size of 800 μm or less, of 700 μm or less, or of 600 μm or less. 
   
   
       47 . The method of  claim 30 , wherein a portion of the powder is treated with solvent, the portion having a weight of less than 1 g. 
   
   
       48 . The method of  claim 47 , wherein at least two portions are treated in parallel. 
   
   
       49 . The method of  claim 30 , wherein treating the powder with solvent comprises extracting the analyte by means of a solvent or solvent mixture. 
   
   
       50 . The method of  claim 49 , wherein the analyte is extracted by means of a sequence of solvents or solvent mixtures. 
   
   
       51 . The method of  claim 49 , wherein the amount of solvent or solvent mixture used is less than 1 mL for each extraction. 
   
   
       52 . The method of  claim 30 , wherein determining the analyte comprises detecting the analyte. 
   
   
       53 . The method of  claim 52 , wherein detecting the analyte is realized by mass spectrometry.